GB2151882A - Surveillance system, in particular for personnel registration in mines - Google Patents

Abstract

The system comprises a portable code-transmitter (transponder) (Fig. 1), a sensing unit (interrogator) Fig. 2 for receiving the signals of the code-transmitter, a signal processing unit 80 connected to the sensing unit, and a data-storing unit connected to the signal processing unit. The code-transmitter is a radio-transmitter (30) having a radio-frequency oscillator with inputs (31,32) connected respectively to a code-generator (10) and to a circuit (40) sensing a high-frequency magnetic field. The sensing unit has a coil L connected to an output of a unit 60 exciting the high-frequency magnetic field and having a control input 61. The sensing unit also has a code-receiver 50 with an input 51 for receiving coded signals from the transponder and outputs 52,53. The output 52 is applied to the control input 61 of the exciting unit 60 for interrupting the h.f. field, and the output 53 to the signal processing unit 80, preferably a microprocessor. <IMAGE>

Description

SPECIFICATION Control system, in particular for personnel registration in mines The invention relates to a control system, in particularfor personnel registration in mines.

In a classical way personnel in mines is registrated by means of so-called tallies having been provided with the personal number. When descending into the mine, the miners hang the tally onto the control board and when leaving the mine, they are taking back the tally. From the tallies having been left on the board number of the miners remaining in the mine can be stated, simultaneously from the personal number their names can be also identified.

The essence of the modernized version of this classical method lies in that every miner has a coded card (provided with a number), which is to be inserted into the proper control slot of a fixed sensing unit, when descending into the mine and coming up therefrom (in a given case also on occasions, when the miner is going from one working place to the other) in order to be able to register the fact of passing. Sensing unit(s) is (are) connected to signal processing and data storing units; these do not only control the staff working in the mine but record the working time spent in the mine, overtime etc. and optionally calculation of wages becomes also possible.

A drawback of said system lies in that active cooperation of the related persons is required, accordingly, subjective errors, negligence, eventual intentional manipulations cannot be excluded. A further drawback lies in that at the control points jams may occur, as taking of the coded card (eventually searching for it) and insertion into the control slot is time consuming. As a further drawback it should be mentioned that the cards may get lost, damaged or mixed up, in addition, direction of passing on the control points cannot be stated, accordingly informations relating to directions are also to be fed.

The aim of the invention is to eliminate said drawbacks, i.e. to develop a control system in particular for personnel recording in mines, by the aid of which on control points control is taking place automatically without the active participation of the persons to be registrated, the means carrying the personal code can be attached to the obligatory equipment of the person (e.g. to the miner's lamp) and which cannot be removed without destruction; in such a manner errors resulting from subjective factors can be avoided, simultaneously an embodiment is also possible, which is automatically detecting the direction of passing.

The task set can be solved by means of a control system, which contains a portable code transmitter, a detector being suitable for the receipt of the signals of the code transmitter, a signal processing unit connected to said detector and a data storing unit connected to the signal processing unit and with said system in accordance with the invention the code transmitter is a radio-transmitter; the radiotransmitter has a radio-frequency oscillator provided with a first and second input and to the first input of which a code generator is connected, while to the second input a circuit is connected sensing the high-frequency magnetic field; the sensing unit is provided with a coil which again is connected to the unit exciting a high-frequency magnetic field, having a control input and output, respectively and with a code-receiving unit, the code-receiver has an input and a first and a second output, while the input is connected to the receiver-detector sensing the signals of the radio-transmitter, the first output is connected to the control input of the exciting unit and the second output to the signal processing unit, being preferably a microprocessor.

With a preferred embodiment of the system according to the invention between the codegenerator and the radio-frequency oscillator a mod ulator is inserted.

With an other preferred embodiment between the code-receiver and the signal processing unit - preferably a microprocessor - a decoding interface circuit is inserted.

At last, with a further preferred embodiment the signal processing unit - preferably a microprocessor - is connected to a program-memory and/or transit memory and/or a central data collector.

In addition to the aforementioned advantages, the advantage of the system according to the invention lies in that the miniature radio-transmitter used as personal code transmitter can be well applied for other control purposes in safety and security technics. When approaching areas forbidden for persons or certain persons it may induce an alarm signal; the radiated signals can facilitate the discovery of persons cut off from the outside world by collapsed rubbish as a consequence of an accident.

The invention will be detailed by means of a preferred exemplary embodiment with reference to the accompanying drawings, wherein: Figure 1 is a block schematic of the code transmitter of a system according to the invention, having been formed as a radio-transmitter; and Figure 2 is the block schematic of the sensing, signal processing and data-storing units of the system.

As it is to be seen in Figure 1, a code-transmitter formed as a radio-transmitter has a 16-bit codegenerator 10, an output 11 of which is connected to an input 21 of a modulator 20. Said modulator 20 operates in frequency shift keying mode. An output 22 of the modulator 20 is connected to a first input 31 of a radio-frequency oscillator 30. A second input 32 of the oscillator 30 is connected to an output 41 of a circuit 40 sensing the high-frequency magnetic field.

An output 33 of the oscillator 30 is simultaneously the aerial of the radio-transmitter.

The code-transmitter is bound to the individual, and its is mounted into the lamp belonging to the obligatory equipment of the miner, and in such a manner that only the competent person could demount it. The code-generator 10 of the codetransmitter is giving a binary information ordered to the given person. Out of the sixteen bits fifteen bits are informative, the remaining one bit is a parity bit.

This way, by means of the code-generator 10, 32, 768 different identifying codes can be produced.

Expediently the code-generator 10 is built-up of CMOS circuit elements in order to reduce size and consumption. The modulator 20 controlled by the code-generator 10 is "superposing" the binary information ordered to a certain person onto the radiofrequency carrier signal having been produced by the oscillator 30.

Oscillator 30 is controlled by the sensing circuit 40, which is e.g. a simple receiver operating in the frequency range between 100 to 300 kHz. The sensing circuit 40 responds to the directed highfrequency magnetic field which is induced by two large-sized elongated coils L being connected to an output 62 of an exciting unit 60 (Figure 2).

A first output 52 of a code-receiver 50 is connected to an input 61 of the unit 60 exciting the highfrequency magnetic field. An input 51 of the codereceiver 50 is connected - in order to be able to receive the signals of the radio-transmitter -to the sensing loop (aerial) having been built-in into coils L or to an output of a radio-frequency receiver 54 provided with an aerial and serving for the same purpose, while a second output 53 is connected to an input 71 of a decoding interface circuit 70. An output 72 of the circuit 70 is connected to an input 81 of a microprocessor 80 forming the signal processing unit. Said microprocessor 80 is provided with a program-memory 86 and a transit memory 88, while an output 82 is connected to an input 91 of an interface 90.An output 92 of the interface 90 is connected via date-transmission line to a central data-collecting unit (not illustrated here).

The high-frequency magnetic field MT induced by the coils L lying perpendicularly to the direction of passing, is about 40 to 50 cm thick and exists as long as the code-transmitter of the passing person penetrates into the radius of action thereof. Thereafter, the oscillator 30 controlled by the sensing circuit 40 (being in ready state) transmits in a quick sequence (sometimes within 10 ms) repeatedly the 16-bit identifying code signal. As a consequence, the code-receiver 50 is stopping the exciting unit 60 and breaks the high-frequency magnetic field, thus preventing radiation of the code-transmitter of a further person arriving in the meantime at the radius of action of the coils L.

After having transmitted the 16-bit code signal n-times, the oscillator is automatically switched-off.

Thereafter the magnetic filed is repeatedly revived and it is able to start again the next code-transmitter.

As the magnetic field is narrow, data-transmission is taking place quickly; thus simuitaneous activation of two different code-transmitters cannot occur. If two sensing units having been separated by a space are applied, direction of passing can be also defined.

The decoding interface circuit 70 connected to the code-receiver 50 produces a binary information from the transmitted code signals and forwards the same on TTL-level to the microprocessor 80.

Digital signals are processed in the microprocessor 80 and forwarded via the interface 90 to the central data-collector. The task of the central datacollector lies in questioning the sensing units, collecting and ranging the data and transmit them to the computer in the dispatcher-centre for further processing.

The microprocessor 80 completes the code received with the identifying code as well as with the code referring to the direction of passing. The date thus obtained contains the information relating to the person, the place of control and direction of passing. These data are completed with the time ot reading bythecentral data-collector. Between the single sensing units (control places) and the datacollector of the personnel registration there is a two-way data-transmission. The sensing unit having been located on the place of descending into the mine is forming an exception, as this unit may receive an information from a central computer too.

Claims (6)

1. A control system comprising a portable codetransmitter, a sensing unit suitable for receiving the signals of the code-transmitter, a signal processing unit connected to the sensing unit, and a datastoring unit connected to the signal processing unit, in which the code-transmitter comprises a radiotransmitter having a radio-frequency oscillator with two inputs connected respectively to a codegenerator and to a circuit sensing a high-frequency magnetic field, the said sensing unit comprising a coil connected to an output of a unit exciting the high-frequency magnetic field and having a control input, and a code-receiver with an input and first and second outputs, the input thereof being connected to sensing means for receiving the signals of the radio-transmitter, the first output to the control input of the exciting unit, and the second output to the signal processing unit.

2. A control system as claimed in claim 1, in which a modulator is inserted between the codegenerator and the radio-frequency oscillator.

3. A control system as claimed in claim 1 or 2, in which a decoding interface circuit is connected between the code-receiver and the signai-processing unit.

4. A control system as claimed in any of claims 1 to 3, in which the signal processing unit is connected to a program-memory and/or a transit memory and/or a central data-collector.

5. A control system as claimed in any of claims 1 to 4, in which the signal processing unit comprises a microprocessor.

6. A control system substantially as described with reference to, and as shown in, the accompanying drawings.